白杨素-铬(Ⅲ)二元配合物增敏荧光法测定环境水样中的痕量总铬

Determination of trace total chromium in water samples using enhancement fluorescence method

基于白杨素?铬(Ⅲ)二元配合物的荧光增敏效应,提出了一种测定环境水体中痕量总铬的荧光新方法.在含一定量甲醇的pH=3.5的HAc-NaAc缓冲溶液中,铬(Ⅲ)与白杨素能形成1∶3的二元荧光配合物,其最大激发波长和发射波长分别为260 nm和429 nm.在优化的测定条件下,铬(Ⅲ)含量在0.480~15.6μg.L-1范围内与荧光强度F呈良好的线性关系,线性回归方程为F=211+46.0C,相关系数r=0.999 3,方法的检出限为0.216μg.L-1(3σ).将样品中的铬(Ⅵ)还原至铬(Ⅲ)形态后再用本法进行测定即得总铬量.对环境水体的电镀废水、黄河水和自来水中总铬测定的回收率为97%~103%;该方法灵敏度高,选择性好,测定操作简单、快速、适用性强.

A new fluorescence method for the determination of trace total chromium in the water samples is proposed based on the fluorescence enhancement effect of chrysin-Cr(Ⅲ) system.In the buffer solution of HAc-NaAc at pH 3.5,Cr(Ⅲ) reacts with chrysin by molar ratio 1∶3,and forms a highly fluorescent active complex in the presence of some methanol.The maximum excitation and emission wavelengths of the complex are 260 nm and 429 nm respectively.Under the optimum conditions,the fluorescence intensity at 429 nm incre...